<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>第六题</title>
</head>

<body>
    <script>
        console.log('我是\“JavaScript\”，JavaScript是一门弱类型语言');
        var js = '我是\“JavaScript\”，JavaScript是一门弱类型语言'
        console.log(js.indexOf("Java"));
        console.log(js.slice(15, 25));
        console.log(js.substr(28));
        console.log(js.replace("JavaScript", "张三"))
        console.log(js.replace("，JavaScript",",JAVASCRIPT"))
        // var js = js.slice(0, js.lastIndexOf("JavaScript")) + js.slice(js.lastIndexOf("JavaScript")).toUpperCase();
        // console.log(js);

    </script>
</body>

</html>